Professional Health Calculators

🎯 What is Body Mass Index (BMI)?

BMI is a screening measurement that compares your weight to your height to categorize body weight status. It's a widely used international standard for assessing whether a person has a healthy body weight.

🔧 How to use this calculator?

1. Select your preferred measurement system (Metric or Imperial)

2. Enter your current weight accurately

3. Enter your height (without shoes for accuracy)

4. Your BMI will be calculated instantly with WHO classification

💼 When to use it?

• Health Screening: Initial assessment of weight status
• Weight Management: Track progress over time
• Medical Consultations: Baseline health indicator
• Insurance Applications: Health risk assessment
• Fitness Goals: Monitor body composition changes

🎯 What is TDEE?

Total Daily Energy Expenditure (TDEE) is the total number of calories your body burns per day, including basal metabolic rate (BMR), physical activity, digestion (thermic effect of food), and non-exercise activity thermogenesis (NEAT).

🔧 How to use this calculator?

1. Select your biological gender (affects metabolic rate)

2. Enter your age (metabolism slows ~2% per decade after 30)

3. Enter your current weight and height

4. Select activity level honestly (overestimating leads to excess calories)

💼 When to use it?

• Weight Loss: Create 300-500 calorie deficit (lose 0.5-1 lb/week)
• Weight Gain: Create 300-500 calorie surplus (gain 0.5-1 lb/week)
• Meal Planning: Establish daily calorie targets
• Nutrition Strategy: Design personalized diet plans
• Fitness Goals: Support muscle building or fat loss

🎯 How is due date calculated?

The calculator uses Naegele's Rule, the standard method established in 1812 and used by obstetricians worldwide. Pregnancy typically lasts 280 days (40 weeks or 10 lunar months) from the first day of the last menstrual period (LMP).

🔧 How to use this calculator?

1. Select the first day of your last menstrual period (LMP) from the date picker

2. The calculator instantly provides:

• Estimated due date
• Current week and day of pregnancy
• Current trimester
• Days until due date

💼 When to use it?

• Pregnancy Planning: Know your estimated delivery date
• Prenatal Care: Schedule appointments at correct weeks
• Work Planning: Plan maternity leave timing
• Baby Preparation: Organize nursery, supplies, classes
• Milestone Tracking: Monitor fetal development stages

🎯 Understanding ovulation and fertility

Ovulation is the release of a mature egg from the ovary, typically occurring 14 days before the next period starts. The fertile window is the timeframe when pregnancy is possible - it includes 5 days before ovulation plus ovulation day itself (6 days total).

🔧 How to use this calculator?

1. Enter the first day of your last menstrual period

2. Enter your average cycle length (count from day 1 of period to day before next period starts)

3. Calculator provides ovulation date, fertile window, and next period prediction

💼 When to use it?

• Conception Planning: Identify best days for intercourse
• Natural Family Planning: Fertility awareness method
• Cycle Understanding: Learn your body's patterns
• Infertility Concerns: Time intercourse optimally (consult RE if not pregnant after 12 months <35 years, or 6 months ≥35 years)
• Ovulation Tracking: Complement with BBT, LH tests, cervical mucus observation

🎯 Why proper hydration matters

Water is essential for every bodily function: temperature regulation, nutrient transport, waste removal, joint lubrication, digestion, cognitive function, and cellular processes. Even mild dehydration (1-2% body weight loss) impairs physical and mental performance.

🔧 How to use this calculator?

1. Enter your current body weight

2. Select your typical daily activity level (exercise duration/intensity)

3. Select your climate conditions (hot weather increases needs)

4. Calculator provides daily water target in liters, cups, and fluid ounces

💼 When to increase water intake?

• Exercise/Physical Activity: +400-800ml per hour of activity
• Hot/Humid Weather: +500-1000ml daily in summer/tropical climates
• High Altitude: +500ml when above 2,500m elevation
• Illness/Fever: Increase 200ml for each degree above 37°C (98.6°F)
• Pregnancy: Add 300ml daily (~2.7L total)
• Breastfeeding: Add 700ml daily (~3.8L total)
• High Fiber Diet: Extra water prevents constipation
• Alcohol Consumption: 1 cup water per alcoholic drink

🎯 Why body fat percentage matters

Body fat percentage is a more accurate health indicator than BMI or weight alone. It distinguishes between lean mass (muscle, bone, organs) and fat mass. Excessive body fat increases risk of cardiovascular disease, type 2 diabetes, certain cancers, and joint problems. Too little body fat impairs hormone production, immune function, and temperature regulation.

🔧 How to use this calculator?

1. Select your biological gender (different essential fat requirements)

2. Enter your age (body composition changes with age)

3. Enter your weight and height

4. Receive body fat percentage with health category classification

💼 When to use it?

• Fitness Tracking: Monitor body recomposition (muscle gain/fat loss)
• Health Assessment: More accurate than BMI for disease risk
• Training Progress: Verify that weight loss is from fat, not muscle
• Goal Setting: Set realistic body composition targets
• Athletic Performance: Optimize power-to-weight ratio

🎯 Understanding ideal body weight

Ideal body weight (IBW) represents a healthy weight range based on height and gender. Unlike BMI, these formulas were developed specifically for medical dosing calculations and health assessments. Multiple formulas are used because ideal weight varies based on body frame, muscle mass, and individual constitution.

🔧 How to use this calculator?

1. Select your biological gender

2. Enter your height accurately

3. Select your body frame size (small/medium/large)

4. Receive ideal weight range with adjustments for frame size

💼 When to use it?

• Weight Loss Goals: Set realistic, healthy target weights
• Medical Reference: Drug dosing, anesthesia calculations
• Health Assessment: Evaluate if current weight is appropriate
• Fitness Planning: Determine optimal competition weight
• Recovery Goals: Target weight for eating disorder recovery

🎯 What is Basal Metabolic Rate?

BMR is the number of calories your body burns at complete rest to maintain vital functions: breathing, circulation, cell production, nutrient processing, protein synthesis, and ion transport. It represents 60-75% of your total daily calorie expenditure and is the foundation for all nutrition planning.

🔧 How to use this calculator?

1. Select your biological gender

2. Enter your age

3. Enter your current weight and height

4. Receive your BMR (calories burned at rest) plus activity multipliers for TDEE

💼 Factors affecting BMR:

• Age: Decreases ~2% per decade after 30 (muscle loss, hormonal changes)
• Gender: Men typically 5-10% higher (more muscle mass)
• Muscle Mass: Each pound of muscle burns 6 cal/day at rest (vs 2 cal/day for fat)
• Genetics: 20-30% variation in metabolic rate between individuals
• Thyroid Function: Hypothyroidism ↓ BMR by 20-40%, hyperthyroidism ↑ BMR
• Body Surface Area: Taller/larger people have higher BMR
• Pregnancy/Lactation: Increases BMR 20-25%
• Extreme Calorie Restriction: Can reduce BMR 15-30% (metabolic adaptation)

🎯 Understanding macronutrients

Macronutrients ("macros") are the three primary nutrients your body needs in large quantities: Protein, Carbohydrates, and Fats. Each has specific functions and provides energy (calories). Optimal distribution depends on your goals, activity level, and metabolic health.

🔧 How to use this calculator?

1. Enter your daily calorie target (use TDEE calculator first)

2. Select your dietary goal/approach

3. Receive macro breakdown in grams and percentages

💼 Macronutrient functions & sources:

• Protein: Muscle repair/growth, enzymes, hormones, immunity. Sources: Meat, fish, eggs, dairy, legumes, tofu. Needs: 0.8-2.2g/kg body weight
• Carbohydrates: Primary energy, brain fuel, glycogen storage. Sources: Grains, fruits, vegetables, legumes. Needs: 45-65% calories (can be lower on low-carb diets)
• Fats: Hormones, cell membranes, vitamin absorption, satiety. Sources: Oils, nuts, avocados, fatty fish. Needs: 20-35% calories (essential fatty acids minimum)

🎯 Understanding heart rate zones

Heart rate training zones are intensity ranges based on percentages of your maximum heart rate (MHR). Each zone targets specific physiological adaptations and energy systems. Training in different zones optimizes cardiovascular fitness, fat burning, endurance, and performance.

🔧 How to use this calculator?

1. Enter your age (determines maximum heart rate)

2. Optionally enter resting heart rate for Karvonen calculation (more accurate)

3. Receive all 5 training zones with specific heart rate ranges and training benefits

💼 Training recommendations:

• Beginners: 80% Zone 2, 20% Zone 3, build aerobic base for 3-6 months
• Intermediate: 70% Zone 2, 20% Zone 3, 10% Zones 4-5
• Advanced: 60-70% Zone 2, 15-20% Zone 3, 10-20% Zones 4-5
• Fat Loss: Focus on Zone 2 (30-60 min), add Zone 3 tempo sessions
• Performance: Periodize with Zone 4-5 intervals (2-3×/week)
• Recovery: Zone 1 only on rest/recovery days

🎯 Understanding blood pressure

Blood pressure measures the force of blood against artery walls. Systolic (top number) = pressure during heartbeat. Diastolic (bottom number) = pressure between beats. Measured in millimeters of mercury (mmHg). Chronic high blood pressure (hypertension) damages arteries, heart, kidneys, brain - leading cause of heart disease and stroke.

🔧 How to use this tracker?

1. Enter systolic pressure (top/first number)

2. Enter diastolic pressure (bottom/second number)

3. Receive classification based on American Heart Association guidelines with recommendations

💼 Measurement best practices:

• Timing: Same time daily, preferably morning before medications/coffee
• Preparation: No caffeine/exercise 30 min before, empty bladder, 5 min rest
• Position: Sit with back supported, feet flat, arm at heart level
• Cuff: Correct size, snug but not tight, on bare skin
• Technique: Don't talk during measurement, take 2-3 readings (average)
• Tracking: Record date, time, readings, medications, symptoms
• White Coat Hypertension: BP elevated at doctor's office but normal at home

🎯 Why pregnancy weight gain matters

Appropriate weight gain during pregnancy supports fetal development, maternal health, and positive birth outcomes. Insufficient gain increases risks of preterm birth, low birth weight, and developmental delays. Excessive gain increases risks of gestational diabetes, hypertension, C-section, postpartum weight retention, and childhood obesity.

🔧 How to use this calculator?

1. Enter your height

2. Enter your pre-pregnancy weight (weight before conception)

3. Select pregnancy type (single or twins)

4. Receive BMI category and recommended total weight gain range

💼 Healthy pregnancy weight gain tips:

• First Trimester: 1-5 lbs total (some lose weight due to nausea)
• Second/Third Trimesters: Steady weekly gain per BMI category
• Nutrition: +340 cal/day (2nd tri), +450 cal/day (3rd tri)
• Quality Focus: Nutrient-dense foods, not "eating for two"
• Exercise: 150 min/week moderate activity if approved by doctor
• Hydration: 10 cups water daily, more if exercising
• Monitoring: Weekly weigh-ins, same time/conditions
• Key Nutrients: Folic acid, iron, calcium, DHA, protein